Port code from prior PR (#1746), code cleanups

include/spdlog/sinks/udp_sink.h

@@ -0,0 +1,87 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <spdlog/sinks/base_sink.h>
+#include <spdlog/details/null_mutex.h>
+#ifdef _WIN32
+#    include <spdlog/details/udp_client-windows.h>
+#else
+#    include <spdlog/details/udp_client.h>
+#endif
+
+#include <mutex>
+#include <string>
+#include <chrono>
+#include <functional>
+
+#pragma once
+
+// Simple udp client sink
+// Connects to remote address and send the formatted log.
+// Will attempt to reconnect if connection drops.
+// If more complicated behaviour is needed (i.e get responses), you can inherit it and override the sink_it_ method.
+
+namespace spdlog {
+namespace sinks {
+
+struct udp_sink_config
+{
+    std::string server_host;
+    uint16_t server_port;
+
+    udp_sink_config(std::string host, uint16_t port)
+        : server_host{std::move(host)}
+        , server_port{port}
+    {}
+};
+
+template<typename Mutex>
+class udp_sink : public spdlog::sinks::base_sink<Mutex>
+{
+public:
+    // connect to tcp host/port or throw if failed
+    // host can be hostname or ip address
+
+    explicit udp_sink(udp_sink_config sink_config)
+        : config_{std::move(sink_config)}
+    {
+
+    }
+
+    ~udp_sink() override = default;
+
+protected:
+    void sink_it_(const spdlog::details::log_msg &msg) override
+    {
+        spdlog::memory_buf_t formatted;
+        spdlog::sinks::base_sink<Mutex>::formatter_->format(msg, formatted);
+        if (!client_.is_init())
+        {
+            client_.init(config_.server_host, config_.server_port);
+        }
+        client_.send(formatted.data(), formatted.size());
+    }
+
+    void flush_() override {}
+    udp_sink_config config_;
+    details::udp_client client_;
+};
+
+using udp_sink_mt = udp_sink<std::mutex>;
+using udp_sink_st = udp_sink<spdlog::details::null_mutex>;
+
+} // namespace sinks
+
+//
+// factory functions
+//
+template<typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> udp_logger_mt(const std::string &logger_name, sinks::udp_sink_config skin_config)
+{
+    return Factory::template create<sinks::udp_sink_mt>(logger_name, skin_config);
+}
+
+} // namespace spdlog